As is known, blenders used for making home-made ice-cream normally comprise a cylindrical, horizontal-axis bowl into which the ingredients for producing a given quantity of ice-cream are poured; a hatch hinged to the outer casing of the blender to rotate about a vertical axis into a closed position closing the inlet of the bowl; an internal cooling unit for cooling and maintaining the bowl and contents at a temperature ranging between −10° C. and −35° C.; and a mixing member mounted for rotation inside the bowl to blend the ingredients at the various ice-cream-making stages.
The hatch in turn substantially comprises a porthole-like cover designed to close the bowl inlet in fluidtight manner, and hinged to the outer casing of the blender, alongside the bowl inlet, to rotate about a vertical axis to and from an operating position closing the bowl inlet. The body of the cover has a central through opening, through which the ice-cream ingredients can be fed into the bowl while the mixing member is rotating inside the bowl; and a peripheral through opening, located close to the bottom peripheral edge of the cover, through which to expel the ice-cream at the end of the blending process.
In addition, the bowl hatch also comprises an ingredient hopper projecting from the cover to feed the ice-cream ingredients through the central through opening; and a safety grille located at the ingredient hopper inlet. The safety grille is obviously fixed to the cover so that it can be removed easily for fast cleaning of the hopper at the end of each operating cycle.
The bowl hatch normally also has a sealing device designed to seal the peripheral through opening in the main body of the cover in fluidtight manner, and to only allow the ice-cream to be expelled at the end of the blending process.
For safety reasons, blenders of the type described above are also equipped with a number of sensors for detecting when the cover is positioned closing the bowl inlet, and when the safety grille is positioned at the ingredient hopper inlet, and for preventing rotation of the mixing member inside the bowl in the event either one of the above components is not in the safe operating position.
Unfortunately, the solutions adopted so far to prevent rotation of the mixing member inside the bowl, in the event the blender is not in the safe operating condition, have proved ineffective. Very often, in fact, the user manages to disable the sensors detecting the presence of the safety grille at the ingredient hopper inlet, and to operate the blender without the grille to pour the ingredients into the bowl faster.